First of all i'd like to suggest creating a new subforum called "pidrive" in "Hardware and peripherals".
tl;dr: Maybe don't connect large external hard drives directly to your RasPi.
This thread is just for sharing my latest experiences with using a external harddrive on a RasPi.
Since WD presented ther pidrive i was a fan of the idea, but also found it very clever marketing: As far as i can tell the pidrive is just a standard external usb drive without housing. Kind of a naked WD Elements drive (the newer ones of course, with the usb controller board).
At first, the only WDLABS invention really dedicated to the RasPi was the pidrive cable. Over time WDLabs provided some clever solutions for the RasPi, including several cases, drives and even boards for the compute kit, that show someone at WD seems to love the RasPi (and is the reason why i think pidrive should have its own subforum).
I decided to grab a used 2TB WD Elements drive from ebay. This drive is now the storage for my KODI RasPi and contains my ripped DVD and audio CD collection. No problems at first but this weekend we watched some movies and experienced random freezes. Of course, a 2TB drive needs lots of power so i assume the freezes are a sign that the RasPi doesn't provide enough power.
I ordered a pidrive cable from WD (too lazy to make my own, because i hate soldering) and will keep you informed if this is the solution for the freezes.